Posted
by
timothyon Saturday January 10, 2009 @08:16PM
from the where-to-throw-wet-towels-now? dept.

JadedApprentice writes "Caught a mention of this startup yesterday on CNBC while they were reviewing the latest gadgets at CES. In the off chance that there was anything remotely feasible or safe about the wireless power prototypes PowerBeam had on display, I took a quick google and found this nice little write-up on the technology (along with some priceless comments for those that scroll down, and I'm not talking about those on the page below).
Bottom line: while it's possibly safe, it may not be efficient and it sure as hell won't power your 1200W gaming rig, the guys at PowerBeam are hoping the convenience of wireless power delivered through directed IR lasers will not only give you the coolest living room in town, but make them very rich in the process"
This may be the only one using lasers, but there's a fair gaggle of wireless power schemes on the floor at CES. Besides several chargers limited to charging the controllers of specific game consoles, I walked through a working high-concept demo put on by PowerMat (also mentioned in that PC Magazine article), which relies on dedicated per-device sleeves and dongles to power cameras, phones, and other necessary pocket-fillers; the sleeve-equipped devices then sit to charge on one of the PowerMat induction mats. That means that if your gizmo isn't one for which a sleeve or dongle is available, you're out of luck, unless it uses AA or AAA batteries (there's a charger made to fit on the mat) or can be powered by USB (for which the company has hockey-puck sized USB-power sources, which, Yes, sit on the induction mat). Impressive, but at $30 a pop, that would mean a fair outlay to convert many gadgets to use such a system.

I'm pretty sure I've seen a video of an IR laser lighting a piece of paper on fire. What's the point of wireless connections like that if you can't walk through them without bursting into flames? You might as well just use a cable. As for what they say about wirelessly charging batteries, well I'd rather see batteries that can flash charge in like 15 seconds. That'd be sweet even if it's wired, which of course it would be. It'd probably take longer to charge the capacitor than the battery too but hey,

Consumers do not consider (quantify) the energy cost of operating some gadget over its lifetime so it is the upfront (manufacturing) price that attracts consumer dollars. And it is cheaper to build a less efficient device than a more efficient one.

The quest for wireless electricity has been going on since the days of Tesla, and despite innumerable dollars spent on research and development, we have made precious little progress. Wireless electricity has again and again proved to be unfeasible, and ultimately, pointless.
I've never understood why people are so eager to find a true wireless electricity system. While it is certainly an interesting novelty to impress people with, it has very little application in the real world. Most devices which are grounded to an outlet are often the kind of objects we don't lug about, like TVs, printers, or cable boxes. None of these devices will benefit from wireless electricity. For the rare device which is portable, but occasionally requires a power connection, like a laptop, the wire tends to be long enough and unobtrusive enough that wireless electricity is just not really an issue.
I think it's safe to say with all the non-news we hear about wireless electricity ever year, I'll be using wireless electricity to power my Phantom console which will run Doom 3.

The killer app for a system like this (though not these specific systems, since they all still expect contact between the device and a wires/dongle) would be in-car power. I personally like to have my GPS in the upper-left corner of the windshield (U.S. driving) and have to make a special effort to ensure that the wire is out of my sight-line. A system that doesn't require dongles in-contact with the wireless power source would be ideal, especially since the devices most people use in-car use small curren

Imagine a wireless power distribution network similar to cell networks. Almost everywhere you go, all of your devices can be powered. No recharging, almost no need for batteries. Imagine if you could run your car on wireless power. No need for gasoline, and no need for expensive and heavy batteries. Imagine running a plane on wireless power.

Of course none of the above is remotely feasible in the near future (maybe ever), but now maybe you understand why people are so eager to find a true wireless electricity system.

there are very large issues that have to be dealt with, mostly the incredible inefficiency.

And the conspiracy by the utility companies. Free energy machines have been invented hundreds of times, but Powergen and their ilk just buy up all the patents and stick them in a basement. I know this guy who saw them while he was putting up the sign that said 'Beware of the Leopard'.

The gross inefficiency of sending enough power through wireless means to a car would far outweigh the benefits of having a car that runs on electricity.

It's like replacing a burning candle with a low power LED that has power transmitted through a laser to it that draws power from the grid. Sure, you might say that you are no longer burning a candle and therefore not releasing carbon dioxide, but the amount of pollution you are creating by removing the candle far outweighs the emissions of the candle. I

Reread your post replacing "wireless power" with "wireless connectivity." Ubiquitous connectivity is more than just convenience of not lugging network cables around. Wireless power has similar potential.

You can't store connectivity in a little box and carry it off with you (you can download a specific thing you want to read or listen to, but you can't download all the conversations you will have). You can store energy in a battery.

The point is that in todays world, most people have a number of portable devices (cell phones, PDA's, laptops, mp players, cameras)and charging them is a bother. You have all the different chargers and more iritating, all the wires around the house. with something like Powermat you can charge up to 6 devices at the same time using just one point of charging and only one wire. It takes the same time as the original charger and uses the same amount of power.

My point (and it wasn't just a bad joke) is that wireless power will only have select uses. If I have to run plumbing in my walls, I might as well run power in my walls. Why go with inefficient wireless power, and drop money on it as well?

There is a nifty-gadget aspect of placing devices on a table and having them charge auto-magically, but for the most part wireless power is a waste.

What about corded devices? Lamps, laptops, etc. I would love to be able to cut the cords to those. Sure, I would still run power in my house. To each room, to stationary devices along walls. But if I can use wireless power within the rooms, I see getting rid of the cords across the room as being great as a convenience factor - and also removes the tripping and pulling hazards.

So, what are the risks that I'll end up powering my retina, rather than my TV, with one of these fancy IR lasers? For very low wattage applications, this wouldn't be a huge deal, assuming the system has a cut-off when the beam is interrupted; but I would hate to have a laser powerful enough to keep a 100watt TV running(through a solar cell no less, efficiency is going to suck) in my eye for even a fraction of a second.

This system just seems impractical at any scale. For the dump-the-gadget-on-the-mat charging scenario, dealing with inductive inefficiencies is going to be easier than dealing with solar cell inefficiency and having to aim the laser at the gadget. For fixed stuff, you are going to have to align the laser and either have a backup battery, or just deal with the device shutting down, if somebody interrupts the beam. Getting wireless power than can follow a moving target around will mean fairly sophisticated tracking and targeting systems, and possibly multiple emitters.

You're probably safe from diffuse reflections at those wavelengths. A direct hit on the eye, either directly or from a specular reflection, would be devastating though, and would in all likelihood damage your cornea and perhaps boil part of your vitreous humour.

Aside from eye safety, note that that power beam will happily set fire to things.

Where do you see that? I only saw on their website that there are using a wavelength "higher than 1400 nm". I'm guessing that means somewhere between 1550 and 1400, which I do not believe the eye (other than the retina!) is opaque to that wavelength. Please correct me if I'm wrong!

Which is much better, because then it is not focused through the lens. Also they seem to have some kind of automatic shutdown if the beam is broken. A momentary pulse of heat to the cornea isn't going to do any real damage.

Go grab a million candlepower spotlight, and aim it at a solar cell across the room. Voila, wattage.

Instead of assuming the kind of lasers you'd expect to see on a shark, assume they're planning on collimating the beam(s) at a larger diameter. If I were to back-of-napkin design such a system, I'd use an array of infrared laser diodes (about 50% efficiency max, these days) in, for a guess, a 7 x 7 array, each laser collimated at abou

How much RFI does this type of device cause ( Yes the IR won't) but...The guy next door trying to work a little DX from the south pacific , and gets creamed by the inadvertent radiation from such a device isnot going to be in a good mood. The "not good" mood could vary , from his giving up radio to burning down your house. Likely the response will be somewhere in between (like frying your electronics). It's surprising what a well directed kilowatt will do.

The problem with power is that it's powerful.The problem with wireless is that there's nothing to contain the information/power you are sending down it.

Thus, sending power over wireless is one of those things that ain't gonna catch on until someone REALLY comes up with a breakthrough... i.e. using some sort of technique that we didn't imagine or utilitising some counter-intuitive quantum principle or something. All the current methods (magnetic induction, pointing a "beam" of some kind) have extremely fatal flaws. At the moment, a 10p bit of copper not only ensures relatively efficient transmission over a much wider range of uses (analog/digital data and power, even simultaneously) but also makes sure it doesn't leak out anywhere and kill anyone by covering it in a millimetre-thick bit of plastic.

A wireless "beam" system is inherently susceptible to obstacles which, we assume, must recieve the power in absence of its intended target. So the power either has to be very low to be safe, or it has to be in a form that won't affect *anything* in its path. I don't think lasers could be said to "not affect things in their path", so it has to be very low power to be safe (what's the safe wattage for a laser in your eye? We're talking 1mW or something). Now, you can get "fancy" without thinking too much - a wider beam, which spreads the power over a small area which has to be beamed to the device etc. but all you're doing is adding more complexity, bulk, components, etc. and reducing convenience.

Magnetic induction is one of those things where the energy is relatively safe (magnetic fields) and, unfortunately, low-power and non-discriminatory about its dissipation - the stuff leaks in all directions wasting more of its (already quite low) power, in 3 dimensions which means that you're now getting useful output power proportional to the inverse cube of your input. If you scale up to larger-power fields you start intefering with other things - inducing currents in nearby metals, playing hell with magnetic devices, wiping credit cards etc. About the only practical use is short-range, low-power devices with their own power store (batteries). You won't be able to use this for anything serious yet and you're coming up with a marvellously complicated replacement for a 10p bit of cable and a mains transformer.

This is one of those problems that we'll bodge solutions to for the next fifty years and then, at some point, discover some fantastic bit of physics that lets us transport large amounts of energy from one place to another without affecting anything en route. The entire principle will be so brilliant that we'll instantly start ditching wired power overnight (probably before we know that it's completely safe). Until then, this "invention" will be consigned to the gimmick / pound shop / toy market and not actually do anything really useful.

Stop faffing about by using stuff that's sitting on a shelf in your inventor's shed to move energy from one place to another. We can do it already, in a myriad of quite obvious (and inefficient, useless) ways but the implicit problem is that the energy we "move" affects things in its path, or is affected by things in its path, to such a degree that it's not viable to use or invest in... until that problem is solved wireless power will not move on.

We did the same with computer data - first it was consigned to copper. Then lots of people came up with lots of fancy ways to try to use it without copper (infrared, microwave, radio, etc.). People were building RS232-Infrared gadgets in their workrooms. It wasn't until there was a fairly reliable, non-line-of-sight, large-enough-range, power-efficient-enough, wide-enough-bandwidth way to do so that people actually starting taking wireless ethernet/bluetooth/etc. seriously.

The rule of thumb I'd use is: Can you do it on a large scale and be useful to the big players? If not, it's pointless trying. This was true of solar - there were specialised uses that could pump investment money into i

Okay, let's do the math. To power my laptop takes about 30 watts. The best infrared detectors are about 30% efficient. So they'd have to beam about 100 watts to the detector. 100 watts hitting one square centimeter of cloth or plastic or paper is enough to start a fire. And way more than enough to blow out an eyeball in a millisecond.

Simple math will not suffice here. In electromagnetics, waves are a form of resonance may be evanescent. Here's a prime example why electrical engineers must use imaginary numbers in their equations.

The trick here is to make the transmitted energy be coherent when directed toward the receiver they want to power and evanescent at all other times. Essentially, they use a particular antenna at both ends and the beam is harmless if anything non-resonant is in the path (including people, pets, and clothing).

Let's think about this for a second. Assume that you want to power a device which draws 200mA at 5V (a number that's the right order of magnitude for small consumer electronics like an iPod). That works out to one watt of power draw.

For the purposes of this calculation, we'll make some extremely generous assumptions:1) The device has a 100% efficient switching converter and can utilize all of the power it receives.2) The device's solar cells are 50% efficient, something which has not been attained even in a laboratory.3) There are no laser transmission losses in the air.

Even under these completely impossible conditions, that would still require a 2-watt laser. For the record, that is four times stronger than a class-3B laser, and those commonly require protective eye-wear to use in the workplace. A 2-watt laser could burn your walls, your skin, or really pretty much anything it wanted.

The only way I would even _consider_ using lasers for powering anything in my home would be if they were:

1) organized in a grid so that the total output power was spread over a couple of square inches instead of a point charge.2) The emitter had a straight beam pattern with minimal diffusion.3) The emitter had an auto shut-off that engaged any time one of a ring of surrounding IR beams were broken. These beams would have to be far enough away from the emitter that the emitter would be able to shut off in-between the time something could break the beams and the time that thing could enter the emitter's path.4) The two devices sat next to each other instead of being across the room. I would not be willing to target high-energy lasers all the way across my living room, but I might be willing to put down a phone with a solar panel on it immediately next to an emitter.

Whats about in a larger scale, I mean what about a laser beam send from Mercury directly to earth, even with all the interferences an the rotations from mercury him self and the Venus you can surely produce enough energy for earth, at least till something goes horrible wrong and we destroy our own planet with the beam....
-I felt a great disturbance in the Force, as if millions of voices suddenly cried out in terror and were suddenly silenced.-

Any laser with more than a few mW is very dangerous to the eye. It's possible to try and make it safe via feedback (you put a small laser on the device that needs to beam at the power laser in order to turn on the power), but, geez, is that really worth it?

A much bigger gain at this point would be standardization three power standards: USB power for low power devices, FireWire power for intermediate power devices, and a single high voltage and high power standard (say 24V). Plus, devices and power supplie